Test whether two references point at the same underlying instance

Does the description disclose side effects, auth requirements, rate limits, or destructive behavior?

Annotations already declare readOnly/idempotent/non-destructive, and the description reinforces rather than contradicts them. Beyond that it discloses the capability dependency (requires compareinstances), the failure path (error when capability missing or an expression fails to evaluate), and a partial return shape ({ Same, TypeA, TypeB }) — useful behavioral context a bare annotation set would not convey.

Agents need to know what a tool does to the world before calling it. Descriptions should go beyond structured annotations to explain consequences.

Is the description appropriately sized, front-loaded, and free of redundancy?

Purpose is well front-loaded, but the trailing metadata block is redundant: 'Non-mutating', 'idempotency=read-only', and 'Safety: read-only' restate the same fact three times, and the signature repeats the schema. It could be trimmed without losing information.

Shorter descriptions cost fewer tokens and are easier for agents to parse. Every sentence should earn its place.

Given the tool's complexity, does the description cover enough for an agent to succeed on first attempt?

There is no output schema, yet the description explains the return shape and error behavior, and it names the capability requirement. For a 3-parameter read-only tool this is essentially complete; only minor gaps like timeout/error field detail remain, and it points to tool-schema for those.

Complex tools with many parameters or behaviors need more documentation. Simple tools need less. This dimension scales expectations accordingly.

Does the description clarify parameter syntax, constraints, interactions, or defaults beyond what the schema provides?

Schema coverage is 100%, so the schema already documents pathA, pathB and threadContext with examples. The description's signature line merely restates the schema and adds no syntax or format meaning beyond it, so the baseline 3 applies.

Input schemas describe structure but not intent. Descriptions should explain non-obvious parameter relationships and valid value ranges.

Does the description clearly state what the tool does and how it differs from similar tools?

States a specific verb (resolve/compare) and resource (two Luau expressions referencing an underlying Roblox instance). It further distinguishes its identity-comparison semantics from `==` or :GetFullName(), which a naive agent might otherwise use, so the tool's niche is unambiguous.

Agents choose between tools based on descriptions. A clear purpose with a specific verb and resource helps agents select the right tool.

Does the description explain when to use this tool, when not to, or what alternatives exist?

Gives a concrete motivating scenario ('confirm "is this captured remote actually game.ReplicatedStorage.RemoteEvent, or a lookalike?"') and states the prerequisite capability and non-mutating nature. It lacks an explicit when-not or a named alternative sibling, so it's clear context without full routing guidance.

Agents often have multiple tools that could apply. Explicit usage guidance like "use X instead of Y when Z" prevents misuse.